Nick Clegg is on Wednesday planning to vote against a cross-party amendment, tabled by socially conservative MPs, that would strip abortion providers of their counselling role.

In the most high-profile parliamentary debate on abortion since the general election, the deputy prime minister will lead a series of Liberal Democrat and Tory ministers into the no lobby. They will be joined by most Labour MPs in voting against the amendment tabled by Nadine Dorries, a Tory backbencher, and Frank Field, Labour's former welfare reform minister.

David Cameron, who was said to be initially sympathetic to the amendment, will vote against it if he is in the Commons. But the prime minister may not be at Westminster for the vote, which will take place after the weekly session of prime minister's questions.

The debate will be the first time parliament has voted on the highly sensitive issue of abortion since MPs voted to maintain the upper limit of 24 weeks in May 2008. Cameron supported an unsuccessful amendment by Dorries to reduce the upper limit to 20 weeks.

The latest Dorries amendment would strip non-statutory abortion providers such as Marie Stopes and Bpas from offering counselling to women. This is designed to provide greater opportunities for independent counsellors, some of whom are influenced by pro-life groups, to provide counselling. NHS abortion providers would still be free to offer counselling.

A rival amendment, tabled by the Lib Dem MP Julian Huppert, has also been accepted for debate. This would prevent any organisation from offering counselling unless it followed "current evidence-based guidance produced by a professional medical organisation specified by the secretary of state".

Huppert said: "My amendment effectively supports the status quo. It says that all advice should be based on the medical evidence that we have."

Evan Harris, the former Lib Dem MP who is advising Huppert, said it was important to ensure that advice was based on medical evidence because some NHS abortion providers were referring women to questionable independent counsellors: "It is unethical for the NHS to be signposting, or even referring, women to organisations which make up information or which seek to persuade women either way though guilt, shame or lies."

The Dorries amendment is expected to be comprehensively rejected by MPs. This means that the Huppert amendment is unlikely to be put to a vote.

Yvette Cooper, the shadow women's minister, accused Cameron on Monday of adopting a "cack-handed" approach to abortion after he appeared to show some sympathy for the Dorries amendment. But sources at the Department of Health – who said that all of its ministers would vote against the Dorries amendment – said that the government had always rejected her amendment.

The sources said that ministers have made clear since the early summer that they favour a consultation on the counselling system for women who experience an unplanned pregnancy. This will first examine whether there are problems with the current system. Once that work has been completed the consultation will examine whether women should be offered independent counselling.

But Diane Abbott, the shadow public health minister who will lead for Labour in the debate, was highly critical of the prime minister: "David Cameron has been entirely disingenuous in his handling of this, making promises to the anti-choice campaign one week, and going back on them the next week. The way the government has responded, prioritising government political strategy over the issues at hand, has shown complete disregard for women and families across the country. The government seems to be unable to properly manage the country's health services.

"The anti-choice campaign has been driven by misinformation, misleading arguments and distortion, and fuelled by the government's appalling handling of this issue. Nadine Dorries and her allies cannot point to any evidence to support their claim that women considering a termination are receiving poor advice at the moment. It is crucial that we maintain women's access to impartial, non-directive and clinical information on pregnancy choices. At the moment, there is a duty for women to be fully informed about the choices available to her – including alternatives to an abortion."